There are a number of operator systems for charging telephone calls to various billing numbers such as the directory number of a calling or called line or a calling card number provided by a telephone operating company. One such operator system is the Traffic Service Position System No. 1 described in The Bell System Technical Journal, Vol. 49, No. 10, December, 1970, and Vol. 58, No. 6, Part 1 of 2, July-August, 1979. This system serves a large number of customer lines through a local telephone exchange by connections to a number of analog trunks between the local office exchange and a toll or transit office exchange to receive and send analog signals to customer lines served by the local exchange. Another operator system is the Operator Services Position System which is a feature of AT&T's 5 ESS.TM. digital switch.
There are also a number of existing credit card reader systems to receive charging information from special credit card reader stations. However, these systems typically require three paths through a local telephone office exchange. Two of these paths are used to establish a connection from the reader station through the office to an intraoffice trunk back through the office to a processor of the system. The third path is from the processor through the office to an interoffice trunk to a toll office that routes the call to the called destination. The processor collects and verifies the credit card number from the reader station, forwards the call to the called destination, and charges the credit card number for the call.
With the advent of interconnect common carriers providing coin phone and credit or calling card phone service at public facilities such as airports, the interconnect carriers want connections to these phones without having to go through a local office exchange and paying access charges. The interconnect carriers also want to provide these services without going through a costly operator system.